Image forming apparatus

Abstract

There is provided an image forming apparatus which can control reciprocation of a carriage and paper feed in a highly accurate manner and form an image of high quality even when paper skews or paper of a different type from that of the paper set is supplied. An ink jet printer ( 1 ) provided with a motion sensor ( 70 ) in a carriage ( 31 ) determines the type of paper (P) by using a paper position signal output by the motion sensor ( 70 ) and changes printing conditions in accordance with the type of paper. Also, the ink jet printer ( 1 ) calculates a moving amount of the carriage ( 31 ), a feed amount and a deviation amount of the paper (P), and controls the reciprocation of the carriage ( 31 ) and the feeding of the paper (P) based on calculated values.

1. An image forming apparatus having a recording device provided to be reciprocable in a width direction of paper that performs recording on the paper, the image forming apparatus comprising:
 a paper position signal generating device that irradiates the paper with a light with coherence and receives a reflected light of the light with coherence to generate a paper position signal with respect to a position of the paper,
 wherein the paper position signal generating device is provided so as to move in synchronization with the recording device in the width direction; and 
 
 a recording device moving amount detection device that detects a recording device moving amount that is a moving amount of the recording device in the width direction by using the paper position signal,
 wherein the recording device moving amount detection device detects the moving amount of the recording device with respect to the paper by chronologically comparing speckle patterns generated by the light being reflected from the paper. 
 
 
   
   
     2. The image forming apparatus as set forth in  claim 1 , wherein the paper position signal generating device is mounted to a carriage that holds the recording device. 
   
   
     3. The image forming apparatus as set forth in  claim 1 , wherein recording on the paper by the recording device in the width direction is controlled by using the recording device moving amount. 
   
   
     4. The image forming apparatus as set forth in  claim 1 , further comprising:
 a paper feed device that feeds the paper; and 
 a paper feed amount detection device that detects a paper feed amount by using the paper position signal. 
 
   
   
     5. The image forming apparatus as set forth in  claim 4 , wherein the feed device is controlled by using the paper feed amount detection device. 
   
   
     6. The image forming apparatus as set forth in  claim 4 , wherein the paper feed amount detection device calculates the paper feed amount by chronologically comparing the speckle patterns generated by the light being reflected from the paper. 
   
   
     7. The image forming apparatus as set forth in  claim 4 , further comprising a deviation detection device that detects deviation when the paper is fed by using the paper position signal. 
   
   
     8. The image forming apparatus as set forth in  claim 7 , wherein a movement of the recording device is controlled based on a deviation amount detected by the deviation detection device. 
   
   
     9. The image forming apparatus as set forth in  claim 8 , wherein a movement of the recording device is controlled such that a position at which recording on the paper is performed is a predetermined position. 
   
   
     10. The image forming apparatus as set forth in  claim 4 , wherein the feeding of the paper is prohibited while the recording device is moved in the width direction,
 and wherein the movement of the recording device in the width direction is prohibited while the paper is fed. 
 
   
   
     11. The image forming apparatus as set forth in  claim 1 , further comprising a paper condition identification device that identifies conditions of the paper by using the paper position signal. 
   
   
     12. The image forming apparatus as set forth in  claim 11 , wherein the paper condition identification device identifies a type of the paper based on the speckle patterns generated by the light being reflected from the paper. 
   
   
     13. The image forming apparatus as set forth in  claim 11 , wherein the recording device changes recording conditions depending on conditions of the paper identified by the paper condition identification device. 
   
   
     14. The image forming apparatus as set forth in  claim 1 , wherein receipt of the light is performed by using a photoreceptor including a plurality of two-dimensionally arranged pixels. 
   
   
     15. The image forming apparatus as set forth in  claim 1 , wherein a position at which the light is reflected on the paper is upstream with respect to a paper feed direction from a position at which the recording device performs recording.